The breakup was "mutual" and "extremely amicable," the insider says, noting that the singers remain close friends, despite reports from other sources that they were "fighting" a lot before the split. As for what went wrong? Though another source previously told Us that Perry's touring schedule was a factor, this pal says they simply "made the mature decision that it was the right time."

Perry, 29, and Mayer, 36, have dated on and off since the summer of 2012. They seemed happy as recently as late January, when they hit up a Grammys after-party together at the Ace Hotel in downtown L.A. "John and Katy were really cute together," an onlooker told Us at the time, noting that the "Paper Doll" crooner was "taking photos of everything and everybody" all night.

Indeed, Perry told Ellen DeGeneres in December that she and her "Who You Love" duet partner "have a lot of fun" — in part because they have so much in common. "We have music as an understanding and love between each other and we connect," the "Roar" singer said. "It's like he understands what I do because he does the same thing. And so after a long day, if it's been tough, I don't really have to go into it. He just gets it."